1. Field of the Invention
The present invention relates generally to Diesel engines and, more particularly, to Diesel engines with EGR control devices.
2. Description of the Prior Art
EGR control devices are used to reduce NOx (nitrogen oxide) emissions from Diesel engines. Typically an EGR control device controls the quantity of exhaust gases that are recirculated to an intake of the engine in response to the engine's rpm rate and load. In prior art devices, the load on the engine is detected by a potentiometer that monitors changes in the operating angle of an accelerating lever whereas the engine's rpm rate is detected by an electromagnetic coil type pick-up. An electromagnetic actuator responds to the detected signals to adjust the opening of an EGR control valve provided in a passage between an exhaust pipe and an intake pipe.
However, one disadvantage of prior EGR control devices is their relatively high cost resulting from the special electric detectors that are used to detect the engine's load and rpm rate and the electromagnetic actuator used to control exhaust recirculation.